The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem and the understanding of the causes of a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section may merely represent different approaches, which in and of themselves may also be inventions.
Fluid filter systems remove impurities from fluids, such as water, so as to fulfill various requirements (e.g., for drinking purpose, medical use, industrial use, etc.). This specification recognizes the need for replacing filters in filter cartridges.